MONDAY, Feb. 6, 2017 (HealthDay News) -- Many people who think they're allergic to penicillin don't really have an allergy to this antibiotic, a pediatric expert says.

And anyone who thinks they have had an allergic reaction to penicillin should undergo an allergy test to ensure they really need to avoid these important drugs, Dr. Min Lee advised. She is a pediatric allergist at UT Southwestern Medical Center at Dallas.

"Penicillins are some of the safest and cheapest antibiotics available, and people who are reported to be allergic often get antibiotics that are costlier and potentially more toxic," Lee said in a news release from the medical center.

According to UT Southwestern researchers, 90 percent of people who have a penicillin allergy listed in their medical records didn't actually have a reaction when exposed to the medication during an allergy test.

Doctors can test for a penicillin allergy in a two-step process. First, they do a skin test. If that result is negative, patients are given an oral penicillin challenge to verify the result. In an oral challenge, people are given the substance they may be allergic to under careful medical supervision to see if a reaction occurs, according to the American Academy of Allergy, Asthma and Immunology.

There are a few different reasons why people may mistakenly think they are allergic to penicillin. Some people who had a reaction in the past eventually outgrow their allergy. Lee urged parents to have their child tested before they transition to adult medical care.

"Even if a child was allergic 10, 15 years ago, they may not be now and if not, it's a good time to get the label removed from health records," Lee suggested.

Viral infections could also be misdiagnosed as a penicillin allergy, she said. In some cases, patients simply don't remember their experience correctly.

It's important to verify a penicillin allergy to avoid taking alternative drugs that increase the risk for side effects. Broad-spectrum antibiotics are prescribed for people who can't take penicillin. These drugs, however, can kill beneficial skin and gut bacteria and potentially contribute to the rise of treatment-resistant superbugs, according to the news release.

"People who have a reported penicillin allergy are more likely to be hospitalized for C. difficile and MRSA -- bacteria that are resistant to multiple antibiotics and can cause life-threatening infections," Lee said.